Malahide is accessible both by bus and rail. Malahide train station is in the town itself. See the Irish Rail website Irish Rail for train times. Malahide train station is on both the DART line and the Suburban commuter lines. The train station is located in the center of town.
There are many bus services that reach Malahide, see the Dublin Bus Website Dublin Bus look for the 42 timetable. The bus runs frequently on every day of the week.
The main bus route from Dublin city centre is the 42 bus which leaves from Abbey Street. The bus stop is near to the Luas tram stop and the Abbey Theatre
The 42 destination will show either Portmarnock (via Seamount) or Malahide (via Seabury), both pass through the centre of Malahide town.
Ask the bus driver for Malahide -- will take about 40 minutes in total. The main bus stop in Malahide is next to the train station, the main bus stop is over the humpback bridge, the train station is on your left-hand side. The bus will stop is outside the church. The return stop is on the other side of the road.
The 32A also runs between Dublin city centre and Malahide. It takes a different route and also has a different start and end point. It runs less frequently than that 42.
Please note that the 42 is very different from the 42A and B.
The main points of interest are Malahide castle and the coastal walk to Portmarnock.
Malahide town is centred on a crossroad: the diamond, called so as the buildings are set back at the junction to form a diamond shape.
Facing the road from the bus stop with the church behind you (this works for the train station also): To the right, over the humpback bridge, it the entrance to Malahide castle demense.
To the left, is the crossroads, beyond is the Grand Hotel and the main route to Portmarnock. The street has many coffee shops and one pub (Duffy's).
Moving towards the crossroad and turning left (downhill) has more coffee shops and two more pubs (Gibney's and Smyth's). It is also the way down to the marina.
A must-see when in Malahide is the castle and its grounds. There are many walks through the woodland which lead to the castle. There is an outdoor playground and many wide-open spaces.
The other main attraction is the coastal walk to Portmarnock that clings to the coast. A walk from Malahide to Portmarnock can take about 40 minutes. You may also want to take a walk along Portmarnock's Velvet Strand. The coast route is exposed and so you should be prepared for windy conditions, there is no shelter along the way if the weather changes.
There are four busses in total that pass between Portmarnock and Malahide if you want to save the walk back; the 32A, 102, 230 all follow the coastal route. Note that the 102 and 230 do not run on Sundays. The fourth bus is the 42 which follows a different route to Malahide but runs more frequently.
There are three main pubs in Malahide: Duffy's, Gibney's and, Smyth's.